Mechanical warewashing machines including dishwashers have been common in the institutional and household environments for many years. Such automatic warewashing machines clean dishes using two or more cycles which can include initially a wash cycle followed by a rinse cycle. Such automatic warewashing machines can also utilize other cycles, for example, a soak cycle, a pre-wash cycle, a scrape cycle, additional wash cycles, additional rinse cycles, a sanitizing cycle, and/or a drying cycle. Any of these cycles can be repeated, if desired and additional cycles can be used. Rinse aids are conventionally used in warewashing applications to promote drying and to prevent the formation of spots on the ware being washed.
In order to reduce the formation of spotting, rinse agents have commonly been added to water to form an aqueous rinse that is sprayed on the dishware after cleaning is complete. The precise mechanism through which rinse agents work is not established. One theory holds that the surfactant in the rinse agent is absorbed on the surface at temperatures at or above its cloud point, and thereby reduces the solid-liquid interfacial energy and contact angle. This leads to the formation of a continuous sheet which drains evenly from the surface and minimizes the formation of spots. Generally, high foaming surfactants have cloud points above the temperature of the rinse water, and, according to this theory, would not promote sheet formation, thereby resulting in spots. Moreover, high foaming materials are known to interfere with the operation of warewashing machines.
In some cases, defoaming agents have been used in an attempt to promote the use of high foaming surfactants in rinse aids. In theory, the defoaming agents can include surfactants with a cloud point at or below the temperature of the rinse water, and would thereby precipitate out and modify the air/liquid interface and destabilize the presence of foam that may be created by the high foaming surfactants in the rinse water. However, in many cases, it has been difficult to provide suitable combinations of high foaming surfactants and defoamers to achieve desired results. For example, for certain high foaming surfactants, it has often been necessary to provide defoaming agents that are chemically quite complicated. For example, Published International Patent Application No. WO89/11525 discloses an ethoxylate defoamer agent that is capped with an alkyl residue.
A number of rinse aids are currently known, each having certain advantages and disadvantages. There is an ongoing need for alternative rinse aid compositions, especially alternative rinse aid compositions that are environmentally friendly (e.g., biodegradable), and that essentially include components that are suitable for use in food service industries, e.g. GRAS ingredients (generally recognized as safe by the USFDA, partial listing available at 21 C.F.R. §§184).
In order to reduce the formation of spotting, rinse aids have commonly been added to water to form an aqueous rinse that is sprayed on the ware after cleaning is complete. A number of rinse aids are currently known, each having certain advantages and disadvantages. There is an ongoing need for alternative rinse aid compositions.
Objects, advantages and features of the present invention will become apparent from the following specification taken in conjunction with the accompanying drawings.
While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention.
Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.